After clearing a run for the first time you will unlock the chance for elevators to side rooms to spawn. You will want to keep an eye out for these and go to the bank every chance you can on multiple runs. In the bank there will be about 4 gold pots that have more money in them than a normal pot. You'll want to put deposit the money you have on you into the bank, this will save it so it can be withdrawn on another run. once your bank vault has over $3,000 you can withdraw it all so you are then carrying it.
Doing this should also earn the following achievements.